From 90a053d203fb5c510201b3984090000c1876adad Mon Sep 17 00:00:00 2001
From: Andrei Golubev <andrei.golubev@qt.io>
Date: Fri, 28 Aug 2020 13:19:33 +0200
Subject: [PATCH] Properly fix issue in qtablewidget.cpp

The original fix done in 4b2f5371d9ba7b8d2dc068223866bbb3c8242beb
actually introduced another subtle issue which should in theory cause
additional overhead. Fixed the behavior to be in fact compatible to the
old one

Task-number: QTBUG-84320
Change-Id: I22b130076f9eedbcf7c5eeae78362adfd0eee9af
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
---
 src/widgets/itemviews/qtablewidget.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/widgets/itemviews/qtablewidget.cpp b/src/widgets/itemviews/qtablewidget.cpp
index ac59271c8d..f4f61369b6 100644
--- a/src/widgets/itemviews/qtablewidget.cpp
+++ b/src/widgets/itemviews/qtablewidget.cpp
@@ -584,12 +584,15 @@ void QTableModel::ensureSorted(int column, Qt::SortOrder order,
     QList<QTableWidgetItem *> newVertical = verticalHeaderItems;
     QList<QTableWidgetItem *> colItems = columnItems(column);
     QList<QTableWidgetItem *>::iterator vit = colItems.begin();
+    qsizetype distanceFromBegin = 0;
     bool changed = false;
     for (int i = 0; i < sorting.count(); ++i) {
+        distanceFromBegin = std::distance(colItems.begin(), vit);
         int oldRow = sorting.at(i).second;
         QTableWidgetItem *item = colItems.at(oldRow);
         colItems.remove(oldRow);
-        vit = sortedInsertionIterator(colItems.begin(), colItems.end(), order, item);
+        vit = sortedInsertionIterator(colItems.begin() + distanceFromBegin, colItems.end(), order,
+                                      item);
         int newRow = qMax((int)(vit - colItems.begin()), 0);
         if ((newRow < oldRow) && !(*item < *colItems.at(oldRow - 1)) && !(*colItems.at(oldRow - 1) < *item))
             newRow = oldRow;